TUESDAY, Dec. 6, 2016 (HealthDay News) -- Cardiac arrest patients who receive epinephrine (adrenaline) within five minutes of their heart stopping are more likely to survive than those who don't receive the drug within that time frame, according to a new study.

Researchers analyzed outcomes among more than 100,000 patients who suffered cardiac arrest while staying at nearly 550 hospitals across the United States. Cardiac arrest occurs when the heart suddenly stops beating, while a heart attack happens when blood flow to the heart is blocked and heart tissue is damaged.

In the study, survival rates were nearly 13 percent among patients who received epinephrine shots within five minutes of their heart stopping. Rates were only 11 percent among those who received the drug after five minutes had passed.

"That is a 20 percent better survival rate for patients at hospitals where epinephrine is given quickly, which is a big difference," said study first author Dr. Rohan Khera, a cardiology division fellow at University of Texas Southwestern Medical Center in Dallas.

The researchers also found that delays in receiving epinephrine shots led to poorer recovery in patients, and that hospitals that dealt with larger numbers of cardiac arrests tended to administer epinephrine shots sooner than those with fewer cases.

About 80 percent of patients who suffer cardiac arrest in a hospital have a condition due to causes that can't be treated with a defibrillator, the researchers explained. They have to be treated with CPR and epinephrine, and they have much lower survival rates than those who can be treated with a defibrillator.

"Treatment options for non-shockable cardiac arrest are so limited that there has been an emphasis on improving current processes," Khera said in a UT news release. "Administering epinephrine promptly and improving the quality of CPR -- these are the easily improved practices, which may be lifesaving."